Hi sir, I need help you ! I have an identical laptop but with the "black screen". My laptop got stuck when updating my BIOS. First I have a question for you: what code does bios chip have? My chip is 25q80xxx - 1mb and the latest bios file on the hp site has 8mb. Thanks for your time.

If only the 15" models came in FHD "HDR-spec" screen option without numpad I positively would buy them in a heartbeat. Are you reading HP? Please make it happen.

Missed a few numbers,

Test 3 was :
733   745   732   660   705   714   738   730   730   701

mean : 719

Test 4 was :
751   747   744   753   754   742   752   750   683  736

mean : 741

I did some quick tests on Cinebench 15.0. and at least the CPU throttling seems to be a pretty straight forward thermal issue.

10 CB iterations per 1 test. Undervolt was managed by ThrottleStop 8.60, Speed Shift had been enabled on all tests (was off on default settings), with a value of 128 so some mild underclocking compared to stock could be expected on all cases.

The laptop stand had 2 60mm fans which I had based on the upper part of the laptop, just under the CPU/GPU.

Test 1 - No (laptop stand) fans, no undervolt

CB scores:
755   711   709   688   690   641   623   628   638

mean : 676

Test 2 - Fans on, no undervolt

742   673   690   696   678   555   700   692   694   695

mean = 682
mean ignoring outlier (555) = 696

There was 45 min of pause between Test 1 and Test 2 (went to the store) so the system was cooled down. Still it seemed to start to throttle faster than Test 1. No idea why. The floor seemed to be higher though.

Test 3 - No fans, -60mV undervolt

733   745   732   660   705   714   738   730   701

mean : 718

Test 4 - Fans, -60mV undervolt

751   747   744   753   754   752   750   683

mean : 742

The 10 iterations is probably too little to see the system stabilise fully, so to see the real gains much longer tests should be done. Anyways, it seems like that if we trust the Cinebench scores it is possible to gain ~10% of sustained multithread performance on a 10min intensive workload by using a laptop stand with fans and applying a relatively conservative underclock. A ~6% performance gain was seen with just the underclock. Keeping this in mind I atleast am going to repaste the CPU when the warranty runs out, and probably going to push the underclock a bit more.

Two other notable exceptions worth amending:

The Spectre does indeed have a high pitched whine that is either attached to c4-state on the processor, or tied to screen brightness (pitch goes up and down based on this). Fortunately, it is only noticeable in a silent room.

Fans "always on" option needs to be disabled in the BIOS. That is why they were always running on this review. As I type this, my Spectre's fans are off... which is why I can hear the aforementioned high pitched buzzing.

PROCHOT needs to be disabled (with something like throttlestop) to properly test this unit. Otherwise it will always throttle the GPU down to 70-75C. It will run hot when stressed (90ish), but the throttling is much more manageable.

To be honest, I think this review needs an update on thermals and performance after this is implemented. We can't really see how it actually compares until then, due to how atrociously HP's updates currently hamstring it.

Just another overpriced poor performing crap...

Their Elitebooks' 700 nits FHD without numpad and maybe I would consider it. Also would like to see some improvements in the 2-in-1 department because this is not entirely ergonomic as a tablet.

Based on the information I could find online, the first units that shipped had a more relaxed thermal policy, but then this advisory came out: support.hp.com/us-en/product/hp-spectre-15-ch000-x360-convertible-pc/16779588/document/c06001575

Apparently the GPU was overheating, and starting with bios version F.13 they started throttling aggressively with a target temp of 70C.

I found about the advisory soon after I ordered the laptop (which I haven't received yet) and I was hoping that HP would have balanced the way they handle thermals with subsequent BIOS updates. However, in one of the screenshots it looks like the BIOS version of the unit tested was F.20 and given that the latest revision is F.21 and it mentions nothing about thermals, I don't think there is much hope.
I also don't think there is a way to downgrade the BIOS to the initial release to test that theory either.